Stop mechanism for sewing-machines.



e. w. NELSON.

STOP MECHANISM FOR SEWING MAGHINES.

APPLICATION FILED JULY 10.1917.

1,2, 1W0 Patented Oct. 22, 1918..

2 SHEETS-SHEET l- G. W. NELSON.

STOP MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JULY I0. I917.

Patented Oct. 22, 1918.

2 SHEETS-SHEET 2.

SI wvwl Iioz E srAT s PATENT OFFICE.

GEORGE w. NELsoN, or CLEVELAND, 01110, ASSIGNOR TO THE STANDARD SEWING MACHINE CCMPANY, 0E CLEVELAND, 01110, A CORPORATION 01 01110.

STOP MECHANISM FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented Get. 22, 1918.

Qriglnal application tiled March 2, 1912, Serial No. 681,208. Divided and this application filed July 10,

- 1917. Serial 110179558.

To all whom it may concern:

Be it known that I, GEORGE W. NELsoN, a citizen of the United States, and resident of Cleveland, in the county of Cuyahoga and State of- Ohio, have invented certain new and useful Improvements in Stop Mechanism for Sewing-Machines, of which the following is 'a specification.

This invention relates to stop mechanism for sewing machines and more particularly to stop mechanism for that class of sewing machines in which successive groups or series of stitches are made at separated points in the work, as for example, in button-sewing machines, such as disclosed in my pending application Serial No. 681,208, of which this present application is a division.

The main object of the invention is to provide an improved mechanism for automatically stopping the machine on the completion of a predetermined series of group of stitches and to effect such stopping quickly and without undue jar or strain on the machine parts.

The stop mechanism employed in the attainment of this object embodies suitable braking devices for engaging opposite sides or faces of a suitable rotary driven member, such as the fast pulley generally employed in these machines, and in connection with these braking devlces means are preferably provided for bringing the brake quickly into action when a spring or other suitable power device controlling the brake is released at the proper point in the operation of the ma chine, to wit, on the completion of the predetermined series or group of stitches.

Referring now, to the accompanying drawings forming part of this specification,

- Figure 1 1s a rear side elevation of a but ton-sewing machine provided with my im-- proved stop mechanism, with the parts shown in the position they occupy upon the sto ping of the machine;

Fig. 2 is a similar view, with the front end of the machine broken away and showing the stop mechanism in the posltion it occupies during the operation of the machine and just prior to sing tripped; and

Fig. 3 is a detail illustratin the construction and operation of one of t e braking devices of the stop mechanism, the view being taken from the front side of the machine or the side opposite that shown in Figs. 1 and 2.

Similar reference characters indicate like parts in the several figures of the drawings.

As the stop mechanism embodying my invention is applicable to various specific types of sewing machines, it will not be necessary to here give any detailed description of the sewing machine shown, as any desired description of this may be had by reference to my aforesaid pending application.

The machine, as shown, embodies a main frame comprising upper and lower portions, 2- and 3, suitably connected and adapted for the support of the various parts (if the operating mechanism. The main driven member of the machineiis illustrated as a fast pulley, 4, associated with a loose or driving pulley, 5, these two pulleys being, as is usual, in the form of hand wheels to permit of their being readily manipulated by the operator. The fast pulley 4 is shown as secured to a main driven shaft 6, which extends substantially fromend to end of the lower section 3 of the frame and from which the several operating parts of the machine are driven through suitable connections in usual manner. Associated with the fast and loose pulleys 4 and 5 is my improved stopping and starting mechanism which will now be described:

One of the principal features of the improved starting and stopping mechanism embodied in the machine shown is the provision of means for engaging the principal driven member or fast pulley 4 at opposite sides thereof when the machineis to be automatically stopped. Two braking surfaces i as;

are provided for this purpose, which surposite sides of said driven member when the machine is to be stopped. In the construction shown the fast and loose pulleys are forced into engagement with each othenby a suitable starting lever, such as 36, having till in line with the center of the pulley .5 a cone-pointed pin 37, holding the two pulleys firmly together. during the time that the operator desires the machine to be running. Associated with the pulleys 4 and 5 is shown another lever, such as 38, of substantially ring form surrounding said pulleys. In this case the two levers 36 and 38 are substantially parallel to each other and suitably pivoted at corresponding ends to the lower half frame of the machine. At its upper end the starting lever 86 is shown as having a forwardly and downwardly extending or overhanging arm, 39, the inner face of the depending portion of which carries a suitable frictional or braking device, 40, in juxtaposition with the forward side of the pulley 4. The rin -shaped lever 38 is also shown as havingnear the upper side thereof a corresponding frictional or braking device, 41, substantially in horizontal alinement with that shown at 40. These two lovers 36 and 38 and the braking devices or pads carried thereby are intended to be moved simultaneously in opposite directions, the main portions of said levers, that is, the levers proper, moving away from each other to apply the brake.and moving toward each other when the brake is removed and the pulleys coupled together. Any suitable means may be employed for operating said levers in this manner provided that said means is such as to efi'ect a quick and powerful application of the brake. In order to accomplish this a toggle connection is preferably combined with a strong spring, 44', the latter serving to effect a quick application of the braking devices 40 and 41 to the pulley 4, while the toggle serves to obtain a powerful grip through said braking device upon the opposite sides of said pulley 4. A toggle connection suitable for this purpose is indicated herein, comprising in this case a pair of links, 42 and 43, connected respectively to the starting lever 36 and to a fixed point on the upper frame-2 of the machine, the links of the toggle at their point of connection being also pivoted to a third link, 44, the upper end of which is in turn piv oted to a rock-arm 45 of a rock shaft, 45, journaled in bearings in lugs projecting from the upper rear end of said main frame 2, said rock shaftalso having secured thereto at its front end two rock arms, 46, and 47, and at its rear end a rocking pawl 48. The rock arm 46 is intended to be operated by" connections from a treadle or other suitable partto start the machine, while the rocking pawl 48 constitutes one element of a holding device or detent, and is adapted to be engaged by a complementary holding element or detent, which in the present case is the hooked upper end, 49, of a long lever, 50, pivoted near the center on a suitable fined portion of the frame of the machine,

resale? and having its lower end suitably faced or beveled, as indicated at 51, for cooperat on with tripping means which will be hereinafter described.

The rock arm 47 is shown as connected by means of a rod, 52, to the free end of a rock arm, 53, secured to one end of a rock shaft, 54, journaled in bearings at the rear enol of the machine and having a pair of eccentrics, 55, formed thereon for cooperation with the forward ends of a pair of substantially horizontal links, 56, the rear ends, of which are connected to the ring-shaped lever 38 near the upper end thereof. The construction of these arts and the mode of organization thereof is such that when the starting lever is moved rearwardly or in a direction to release the driving pulley from the driven pulley the toggle is straightened, and at the same time, through the connections from the rock shaft 45 to the rock shaft 54, the links 56 are moved forward slightly by the eccentrics 55, their movement being small as compared with the rearward movement of the starting lever, and the two braking devices 40 and 41 are brought instantaneously and with powerful combined spring and toggle action, into braking engagement with opposite sides of the pulley 4 to stop the machine. in connection with these braking devices means will preferably be employed for assuring the stopping of the machine each time with all of the parts in a predetermined position, to wit, with the take-up 13 in raised position to take the first stitch of the next succeeding series. The means here used for this purpose is a wedge for increasing the friction opposed to the rotation of the parts at a predetermined point. Such a wedge or cam is shown at 4 on the pulley 4 and cooperates with the braking device 40 on the starting lever 36 and the braking device 41 on the ring-lever 38 to wedge said pulley between said braking surfaces and ring the machine quickly, but with a properly grad uated action, to a stop at the exact point desired. Tostart the machine the operator presses down a treadle or other suitable device and through suitable connections, one of which is shown at 57, to the rock arm 4t}, the rocking pawl '48 is drawn down until it passes below th hook 49 of the detent lever 50 when it is engaged by said hook or detent, as shown in Fig. 2, which is normally forced toward said rocking pawl, as by means of a spring 58. lhis movement of the connecting rod 5? serves to release the toggle and withdraw the braking devices from the opposite faces of the pulley 4, and in these positions the parts are held by the detent just described until the lever 50 is tripped automatically on the completion of a predeter-. mined series or group of stitches.

Any suitable means may be employed for efiecting the tripping of the devices described. Preferably, however, suitable releasing or trip ing means operated from the main shaft 6 t rough a cross shaft, such as 59, will be employed. Here this cross shaft is journaled in suitable bearings n the lower frame member 3 of the framlng, and is driven from the main shaft by suitable worm gearing, (not shown) by means of which a relatively slow rotary movement 1s 1mparted to said cross shaft 59. On the completion ofthe making of a predetermined number of stitches a suitable releaslng device may be brought into operation by sa d cross shaft. In the construction shown said cross shaft carries at its rear end a rela tively thick disk 62, in which one or more radially movable pins, such as 63, ma be supported for sliding movement. hese pins may be held either in or .out of operative position as by suitableclamp ng devices, such as 64. Where a single pm projects, as shown in the drawlngs, the automatic stop mechanism will be tripped once on each complete rotation of the cross shaft 59; whereas if both of the pins shown so project said stop mechanism will be tripped twice on such rotation of the cross shaft. Both of these pins may be drawn in and securely clamped out of action when it is desired to use the machine for straight-away stitchin without automatic stoppage of the mechanism periodically. On the completion of the predetermined rotary movement of the shaft 59 and the disk 62,that is, on the completion of the making of the predetermined series or group of stitches, the pin 63 will come in contact with one of the faces 51 of the detent lever 50 and release the lever from the rocking pawl 48, whereupon the automatic stopping of the mechamsm will ensue, as previously described. The tripping means illustrated is shown as normally covered by a swinging plate, such as 65.

What I claim is 1. In a sewing machine and in combination, rotary drivin and driven members, a starting lever there or, stitch-forming mechanism, and an automatic stop mechanism comprising a pair of braking surfaces at opposite sides of said driven member and normally out of engagement therewith and one of which is carried by said starting lever, and means for bringing said surfaces into engagement with opposite sides of said driven member.

2. In .a sewing machine and in combination, rotary driving and driven members, a starting lever therefor, a second lever, stitch-forming mechanism, and an automatic stop mechanism comprising a pair of braking devices at opposite sides of said driven member and normally out of engagement therewith and carried respectively by said levers, and means for simultaneously moving said levers in opposite directions to bring said braking surfaces into engagement with opposite sides of said driven member.

3. In a sewing machine and in combination, rotary driving and driven members, stitch-forming mechanism, and an automatic stop mechanism comprising a pair of braking devices at opposite sides of said driven member and normally out of engagement therewith, means including a spring tending to bring said braking surfaces into engagement with opposite sides of said driven member, and a detent normally restraining said spring.

4. In a sewing machine and in combination, rotary driving and driven members, stitch-forming mechanism, and an automatic stop mechanism comprising a pair of braking devices at opposite sides of said driven member and normally out of engagement therewith, means including a spring tending to bring said braking surfaces into engagement with opposite sides of said driven member, a detent normally restraining said spring, and means for tripping said detent.

5. In a sewing machine and in combination, rotary driving and driven members, stitch-forming mechanism, and an automatic stop-mechanism comprising a pair of braking devices at opposite sides of said driven member and normally out of engagement therewith, means including a toggle connection and a spring for bringing said surfaces into engagement with opposite sides of said driven member, a detent normally restraining said spring, and means associated with the stitch forming mechanism for auto matically tripping said detent on the completion of a predetermined group of stitches.

6. In a sewing machine and in combination, rotary driving and driven-members, a main shaft driven thereby, stitch-forming mechanism, and an automatic stop mechanism comprising a pair of braking surfaces at opposite sides of said driven member and normally out of engagement therewith, means normally under restraint for bringing said surfaces into engagement with opposite sides of said driven member, "nd releasing means controlled by the main shaft for permitting the operation of said last mentioned means.

7 In a sewing machine and in combination, rotary driving and driven members, a main shaft driven therebmstitch-forming mechanism, and an automatic stop mechanism comprising a pair of braking surfaces at opposite sidespf said driven member and normally out of engagement therewith, means normally under restraint for bringing said surfaces into engagement with opposite sides of said driven member, a cross shaft operated by the main shaft, and a trip actuated by said cross shaft for releasing said last mentioned means.

8. In a sewing machine and in combination, rotary driving and driven members, a starting lever therefor, a pivoted ring adjacent to said driven member, stitcht'orming mechanism, and an automatic stop mechanism comprising a pair of braking surfaces at opposite sides of said driven member and normally out of engagement therewith and carried respectively by said starting lever and said ring, and means for simultaneously moving said starting lever and said ring in opposite directions to bring said braking surfaces into engagement with opposite sides of said driven member.

9. In a sewing machine and in combination, rotary driving and driven members, stitch-forming mechanism, and an automatic stop mechanism comprising a pair of braking devices at opposite sides of said driven member and normally out of engagement therewith, and means including a toggle connection and a spring for normally straightening said toggle for bringing said surfaces into engagement with opposite sides of said driven member, said driven member being provided with a cam surface for cooperating with the braking devices to bring the machine to a gradual stop with its parts in predetermined positions.

10. In a sewing machine and in combination, rotary driving and driven members, stitcha orming mechanism, and an automatic stop mechanism comprising a pair of braking devices at opposite sides of said driven member and normally out of engagement therewith, and means for bringing said surfaces into engagement with opposite sides of said driven member, said driven member being provided with a cam surface fordriven member and normally out of engagement therewith, and means for bringing said surfaces into engagement with opposite sides of said driven member, said driven member being provided with means for cooperating with the braking devices to increase the triction opposed to the rotation of the member at a predetermined point, for the purpose set forth.

Signed at Cleveland, in the county of Cuyahoga and State of Uhio, this 2nd day or" July, A. D. 1917.

GEORGE W. NELSQN.

Nitiresses W. l-lrsnor, U KNArr. 

